Monsegur, who had even tried to pass himself off as a federal agent, operated out of his Lower East Side home, according to the criminal complaint.

The hackers allegedly stole personal information about more than 1 million people, with one defendant — Jeremy Hammond, 27, of Chicago — charged in connection with more than $700,000 worth of unauthorized credit-card purchases.

The four others charged are Ryan Ackroyd, 23, and Jake Davis, 29, both of the United Kingdom; and Darren Martyn, 25, and Donncha O’Cearrbhail, 19, both of Ireland.

A law-enforcement source said the charges capped an FBI probe that began in June 2011 following receipt of a confidential tip.

The hacks include “denial of service” attacks led by Monsegur against the Visa, Mastercard and PayPal Web sites between December 2010 and June 2011 in retaliation for the companies’ refusal to process donations to Wikileaks.

Other cyber-attacks targeted confidential information about subscribers and clients of Stratfor, a private intelligence firm; the HB Gary security firm; the Sony Pictures Web site; and Fox Broadcasting, from which information about 70,000 potential “X-Factor” contests was taken.

O’Cearrbhail is charged with hacking into the private email account of an Irish national police officer, then using the information to listen in on a Jan. 17 conference call between the FBI and international law-enforcement agencies about ongoing probes of Anonymous and other groups.

A law-enforcement source said all of the overseas defendants had been arrested previously, with O’Cearrbhail and Ackroyd re-arrested earlier today.

It was unclear when they might be extradited to the US.

Hammond was arrested late yesterday and was expected to appear today in Chicago federal court.

Authorities said it marked the first significant prosecution of major Internet hackers.

According to court papers, members of the group got their start as part of a large worldwide hacking organization known as Anonymous, which authorities said has been operating at least since 2008.

In chat rooms and on Twitter, Anonymous supporters erupted into a chorus of disappointment, confusion, and anger. Some wondered whether the news was an elaborate fraud. Others revisited earlier suspicions that Sabu was a government agent.

As members of Anonymous surveyed the damage Tuesday, one of its most popular Twitter feeds assured its followers that it was still OK.

“We’re sailing close to the wind,” the feed read. “Our crew is complete and doing fine.”

Monsegur was portrayed in court papers as the ringleader of some of the group’s more infamous deeds. Authorities said he formed an elite hacking organization last May — a spinoff of Anonymous — and named it “Lulz Security” or “LulzSec.” “Lulz” is Internet slang that can mean “laughs” or “amusement.”

LulzSec members attained notoriety last May by attacking the PBS website and planting the false story about Shakur. According to court papers Tuesday, Monsegur and others did it in retaliation for what they perceived to be unfavorable news coverage of Wikileaks on the PBS news program “Frontline.”

In July, when LulzSec’s attacks were grabbing world headlines, an unknown person alleged that Sabu was Monsegur, publishing his personal details on the Internet. Sabu took to Twitter to deny that he had been exposed, and as Anonymous’s attacks continued, suspicions eased.

Barrett Brown, a former journalist who became closely associated with Anonymous, said Sabu’s betrayal would have a serious effect on Anonymous.

“He was an admired Anon,” he said. “He’s been a leader. People came to him with information. God knows what else he told them.”